# a = b = 20
# print(a)
# print(b)

a = 10
b = 20
# temp = a
# a = b
# b = temp
# print(a)
# print(b)
# print(a,b)

# 使用多元赋值，直接一步到位完成交换
a, b = b, a
print(a)
print(b)
print(a,b)